1. Field of the Invention
The present invention relates to the field of composite molding for blades used with wind generators of electricity.
2. Description of the Related Art
Many molds and techniques for working with composite materials have been developed in the past. Many of them look for different means to affect the critical process of curing the composite material being used. Most of the molds in the prior art rely on either large ovens or external ducts to control the temperature of the mold, and indirectly the temperature of the material inside the mold during setting or curing. The use of ovens for these elongated blades is clearly impractical. One of these molds is disclosed in Spanish patent No. ES 2,089,965 wherein a large oven is required. Another example of a mold used in the industry is the one disclosed in Spanish patent No. ES 2,007,179 where the two halves are subsequently attached together. The use of laminar enlargement is disclosed in Messerschmidt patent No. ES 8,503,080 with an oven. The use of fiberglass cloth with polypropilene threads or fibers is described in European patent No. EP 856,900 but, again, the molde is introduced in an oven. Some designs include mechanisms for introducing air inside the mold. One of these designs is the one disclosed by Lemelson in U.S. Pat. No. 4,043,721 for a composite body molding apparatus. The patented mold, however, uses a pipe 26 to deliver hot air inside the mold to affect the curing process. A number of holes in pipe 26 deliver the hot air in certain areas of the material but the temperature gradient is not uniform. In the present invention, on the other hand, perforated skins of the composite article being molded thereby not only obviating the need to use a pipe or other means of introducing and routing the hot air inside the mold but also the present invention achieves a more uniform temperature gradient for the article being formed.
Other patents describing the closest subject matter provide for a number of more or less complicated features that fail to solve the problem in an efficient and economical way. None of these patents suggest the novel features of the present invention.